#include <stdio.h>
//課題B-1: 1からnまでの和を求めるコードを完成させてください
int sum(int n){
	int i;
	int c;
	for(i = 0; i < n; i++){
	c = c + i; 	
	}
	return c;
 
}
 
int main(void) {
	int a,b;
    a = 10;
    b = sum(a);
	return 0;
}
 
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