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ctype-mismatchmsp430

Integral type error when adding float to integer

I'm working on implementing circle drawing graphics on an embedded device using C. I've precalculated the trig lookup tables for sin and cos and stored them as const float arrays. The IDE I'm using(Code Composer Studio for the MSP430) throws an error anytime I try to add a value from one of the lookup arrays to the newX or newY variables. The error message states: "../main.c", line 61: error #31: expression must have integral type which corresponds to this line: newX = (int) (newX + cosTable[i]);

Full code:

#include <msp430.h>
#include "OLED.h"
#include "math.h"
#include "graphics.h"
void graphics_circle(int x, int y, int radius);
void main(void) {

    WDTCTL = WDTPW + WDTHOLD; // Stop WDT

    init();
    Delay_ms(1000);
    graphics_circle(32, 32, 16);

    while(1)
    {

    }


}

const float sinTable[] = {0.0, 0.018, 0.035, 0.053, 0.07, 0.088, 0.105, 0.122, 0.14, 0.157, 0.174, 0.191, 0.208, 0.225, 0.242, 0.259, 0.276, 0.293, 0.31, 0.326, 0.343, 0.359, 0.375, 0.391, 0.407, 0.423, 0.439, 0.454, 0.47, 0.485, 0.5, 0.516, 0.53, 0.545, 0.56, 0.574, 0.588, 0.602, 0.616, 0.63, 0.643, 0.657, 0.67, 0.682, 0.695, 0.708, 0.72, 0.732, 0.744, 0.755, 0.767, 0.778, 0.789, 0.799, 0.81, 0.82, 0.83, 0.839, 0.849, 0.858, 0.867, 0.875, 0.883, 0.892, 0.899, 0.907, 0.914, 0.921, 0.928, 0.934, 0.94, 0.946, 0.952, 0.957, 0.962, 0.966, 0.971, 0.975, 0.979, 0.982, 0.985, 0.988, 0.991, 0.993, 0.995, 0.997, 0.998, 0.999, 1.0, 1.0, 1.0, 1.0, 1.0, 0.999, 0.998, 0.997, 0.995, 0.993, 0.991, 0.988, 0.985, 0.982, 0.979, 0.975, 0.971, 0.966, 0.962, 0.957, 0.952, 0.946, 0.94, 0.934, 0.928, 0.921, 0.914, 0.907, 0.899, 0.892, 0.883, 0.875, 0.867, 0.858, 0.849, 0.839, 0.83, 0.82, 0.81, 0.799, 0.789, 0.778, 0.767, 0.755, 0.744, 0.732, 0.72, 0.708, 0.695, 0.682, 0.67, 0.657, 0.643, 0.63, 0.616, 0.602, 0.588, 0.574, 0.56, 0.545, 0.53, 0.516, 0.5, 0.485, 0.47, 0.454, 0.439, 0.423, 0.407, 0.391, 0.375, 0.359, 0.343, 0.326, 0.31, 0.293, 0.276, 0.259, 0.242, 0.225, 0.208, 0.191, 0.174, 0.157, 0.14, 0.122, 0.105, 0.088, 0.07, 0.053, 0.035, 0.018, 0.001, -0.017, -0.034, -0.052, -0.069, -0.087, -0.104, -0.121, -0.139, -0.156, -0.173, -0.19, -0.207, -0.224, -0.241, -0.258, -0.275, -0.292, -0.309, -0.325, -0.342, -0.358, -0.374, -0.39, -0.406, -0.422, -0.438, -0.453, -0.469, -0.484, -0.5, -0.515, -0.529, -0.544, -0.559, -0.573, -0.587, -0.601, -0.615, -0.629, -0.642, -0.656, -0.669, -0.681, -0.694, -0.707, -0.719, -0.731, -0.743, -0.754, -0.766, -0.777, -0.788, -0.798, -0.809, -0.819, -0.829, -0.838, -0.848, -0.857, -0.866, -0.874, -0.882, -0.891, -0.898, -0.906, -0.913, -0.92, -0.927, -0.933, -0.939, -0.945, -0.951, -0.956, -0.961, -0.965, -0.97, -0.974, -0.978, -0.981, -0.984, -0.987, -0.99, -0.992, -0.994, -0.996, -0.997, -0.998, -0.999, -0.999, -1.0, -0.999, -0.999, -0.998, -0.997, -0.996, -0.994, -0.992, -0.99, -0.987, -0.984, -0.981, -0.978, -0.974, -0.97, -0.965, -0.961, -0.956, -0.951, -0.945, -0.939, -0.933, -0.927, -0.92, -0.913, -0.906, -0.898, -0.891, -0.882, -0.874, -0.866, -0.857, -0.848, -0.838, -0.829, -0.819, -0.809, -0.798, -0.788, -0.777, -0.766, -0.754, -0.743, -0.731, -0.719, -0.707, -0.694, -0.681, -0.669, -0.656, -0.642, -0.629, -0.615, -0.601, -0.587, -0.573, -0.559, -0.544, -0.529, -0.515, -0.5, -0.484, -0.469, -0.453, -0.438, -0.422, -0.406, -0.39, -0.374, -0.358, -0.342, -0.325, -0.309, -0.292, -0.275, -0.258, -0.241, -0.224, -0.207, -0.19, -0.173, -0.156, -0.139, -0.121, -0.104, -0.087, -0.069, -0.052, -0.034, -0.017, -0.0, };
const float cosTable[] = {1.0, 1.0, 1.0, 0.999, 0.998, 0.997, 0.995, 0.993, 0.991, 0.988, 0.985, 0.982, 0.979, 0.975, 0.971, 0.966, 0.962, 0.957, 0.952, 0.946, 0.94, 0.934, 0.928, 0.921, 0.914, 0.907, 0.899, 0.892, 0.883, 0.875, 0.867, 0.858, 0.849, 0.839, 0.83, 0.82, 0.81, 0.799, 0.789, 0.778, 0.767, 0.755, 0.744, 0.732, 0.72, 0.708, 0.695, 0.682, 0.67, 0.657, 0.643, 0.63, 0.616, 0.602, 0.588, 0.574, 0.56, 0.545, 0.53, 0.516, 0.501, 0.485, 0.47, 0.454, 0.439, 0.423, 0.407, 0.391, 0.375, 0.359, 0.343, 0.326, 0.31, 0.293, 0.276, 0.259, 0.242, 0.225, 0.208, 0.191, 0.174, 0.157, 0.14, 0.122, 0.105, 0.088, 0.07, 0.053, 0.035, 0.018, 0.001, -0.017, -0.034, -0.052, -0.069, -0.087, -0.104, -0.121, -0.139, -0.156, -0.173, -0.19, -0.207, -0.224, -0.241, -0.258, -0.275, -0.292, -0.309, -0.325, -0.342, -0.358, -0.374, -0.39, -0.406, -0.422, -0.438, -0.453, -0.469, -0.484, -0.499, -0.515, -0.529, -0.544, -0.559, -0.573, -0.587, -0.601, -0.615, -0.629, -0.642, -0.656, -0.669, -0.681, -0.694, -0.707, -0.719, -0.731, -0.743, -0.754, -0.766, -0.777, -0.788, -0.798, -0.809, -0.819, -0.829, -0.838, -0.848, -0.857, -0.866, -0.874, -0.882, -0.891, -0.898, -0.906, -0.913, -0.92, -0.927, -0.933, -0.939, -0.945, -0.951, -0.956, -0.961, -0.965, -0.97, -0.974, -0.978, -0.981, -0.984, -0.987, -0.99, -0.992, -0.994, -0.996, -0.997, -0.998, -0.999, -0.999, -1.0, -0.999, -0.999, -0.998, -0.997, -0.996, -0.994, -0.992, -0.99, -0.987, -0.984, -0.981, -0.978, -0.974, -0.97, -0.965, -0.961, -0.956, -0.951, -0.945, -0.939, -0.933, -0.927, -0.92, -0.913, -0.906, -0.898, -0.891, -0.882, -0.874, -0.866, -0.857, -0.848, -0.838, -0.829, -0.819, -0.809, -0.798, -0.788, -0.777, -0.766, -0.754, -0.743, -0.731, -0.719, -0.707, -0.694, -0.681, -0.669, -0.656, -0.642, -0.629, -0.615, -0.601, -0.587, -0.573, -0.559, -0.544, -0.529, -0.515, -0.5, -0.484, -0.469, -0.453, -0.438, -0.422, -0.406, -0.39, -0.374, -0.358, -0.342, -0.325, -0.309, -0.292, -0.275, -0.258, -0.241, -0.224, -0.207, -0.19, -0.173, -0.156, -0.139, -0.121, -0.104, -0.087, -0.069, -0.052, -0.034, -0.017, -0.0, 0.018, 0.035, 0.053, 0.07, 0.088, 0.105, 0.122, 0.14, 0.157, 0.174, 0.191, 0.208, 0.225, 0.242, 0.259, 0.276, 0.293, 0.31, 0.326, 0.343, 0.359, 0.375, 0.391, 0.407, 0.423, 0.439, 0.454, 0.47, 0.485, 0.501, 0.516, 0.53, 0.545, 0.56, 0.574, 0.588, 0.602, 0.616, 0.63, 0.643, 0.657, 0.67, 0.682, 0.695, 0.708, 0.72, 0.732, 0.744, 0.755, 0.767, 0.778, 0.789, 0.799, 0.81, 0.82, 0.83, 0.839, 0.849, 0.858, 0.867, 0.875, 0.883, 0.892, 0.899, 0.907, 0.914, 0.921, 0.928, 0.934, 0.94, 0.946, 0.952, 0.957, 0.962, 0.966, 0.971, 0.975, 0.979, 0.982, 0.985, 0.988, 0.991, 0.993, 0.995, 0.997, 0.998, 0.999, 1.0, 1.0, 1.0, };

void graphics_init(){
    OLED_Init();
}
void graphics_circle(int x, int y, int radius){
    float i = 0;
    int newX = 0;
    int newY = 0;
    for(i = 0; i < 360; i+=1){
        newX = x;
        newX = (int) (newX + cosTable[i]);
        //newX = x + (int)cosTable[i];//*radius);
        //newY = y + (int)sinTable[i];//*radius);
        OLED_DrawPoint(newX, newY, 0);
    }
}
Solution

  • Apart from the obvious algorithmic problem,

    You're using float as array indexing.

    Use integral value. Say, int i = 0;