嵌入式开发常用方法

// 数字字符串转数字
float toNumber(char amount[]) {
	char i = 0;
	char j = 1;
	float res = 0;
	float float_sector = 0;
	char isFloat = 0;
	while(amount[i] != '\0') {
		if(amount[i] == '.') {
			isFloat = 1;
			i++;
			break;
		}
		printf("%d\r\n", amount[i]-48);
		res = amount[i]-48 + 10 * res;
		i++;
	}
	
	while(isFloat && amount[i] != '\0') {
		float_sector = (amount[i]-48) / (x_pow_y(10.0, j)) + float_sector;
		printf("%f", float_sector);
		i = i + 1;
		j = j + 1;
	}
	return res + float_sector;
}

// 求某个数的n次方
float x_pow_y(float x, char y) {
	if(y == 0) return 1;
	char i = 1;
	float res = 1;
	while(i <= y) {
		res = res * x;
		i = i + 1;
	}
	return res;
} 

void main() {
	char test_str[10] = "123.4567";
	float res;
	res = toNumber(test_str);
	printf("%.4f", res); 
}
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