字符型數字轉換成數值型

 

#include <stdio.h>
void main() {
	int stoi(char str[]);
	char str[10];
	printf("input a digit string:\n");
	scanf("%s", str);
	printf("\nThe value is :%d", stoi(str));
}

int stoi(char str[]) {
	int value = 0, i = 0;
	while(str[i] != '\0') {
		value = value * 10 + str[i] - 48;
		i++;
	}
	return(value);
}