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@@ -0,0 +1,32 @@
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+#include <iostream>
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+
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+int main3()
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+{
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+
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+ //1、单精度 float
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+ //2、双精度 double
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+ //默认情况下 输出一个小数,会显示出6位有效数字
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+
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+ float f1 = 3.14f;
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+ std::cout << "f1 = " << f1 << std::endl;
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+
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+ double d1 = 3.14;
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+ std::cout << "d1 = " << d1 << std::endl;
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+
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+ //统计 float 和 double 占用的内存空间
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+ std::cout << "float占用的内存空间: " << sizeof(float) << std::endl;
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+
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+ std::cout << "double占用的内存空间: " << sizeof(double) << std::endl;
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+
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+ //科学计数法
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+ float f2 = 3e2; // 3*10^2
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+ std::cout << "f2 = " << f2 << std::endl;
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+ float f3 = 3e-2; // 3*0.1^-2
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+ std::cout << "f3 = " << f3 << std::endl;
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+
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+
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+ system("pause");
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+
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+ return 0;
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+
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+}
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