Solidity Tutorial : all about Literal Numbers

Integers numbers

Integers in Solidity can be signed or unsigned.

An int8 will accept values positive and negative values ranging from -128 to 128.

An uint8 will accept values only positive values ranging from 0 to 256 By default, the type int and uint assigns 256 bytes. However, you can specify the number of bytes by range of 8, ranging from 8 to 256.

Because the idea behind these articles is "all about", we must describe everything ! ^^ The table below summaries all the minimum and maximum values for every single possible type of int and uint.

picture here Assign precisely the number of bytes to an integer can enable to use less gas and takes up less storage space on the EVM.

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Fixed point numbers

Use the keyword fixed or ufixed.

Arithmetic Overflow and Underflow

As we have seen, integers are a fixed-size data type and an integer variable has a certain range of numbers it can represents.

If you try to add a number over the range of your integer (eg: 256 for an uint8 that can hold a value up to 255), the result will be overflowed. In this scenario, the value of the variable will be simply 0.

[Show an example here with Remix code]

Warning about numbers

Never use a floating point number in a Financial System because of potentially unexpected behaviour.

Type	Max Value
uint8	255
uint16	65 535
uint24	16 777 215
uint32	4 294 967 295
uint40	1 099 511 627 775
uint48	281 474 976 710 655
uint56	72 057 594 037 927 935
uint64	18 446 744 073 709 551 615
uint72	4 722 366 482 869 645 213 695
uint80	1 208 925 819 614 629 174 706 175
uint88	309 485 009 821 345 068 724 781 055
uint96	79 228 162 514 264 337 593 543 950 335
uint104	20 282 409 603 651 670 423 947 251 286 015
uint112	5 192 296 858 534 827 628 530 496 329 220 095
uint120	1 329 227 995 784 915 872 903 807 060 280 344 575
uint128	340 282 366 920 938 463 463 374 607 431 768 211 455
uint136	87 112 285 931 760 246 646 623 899 502 532 662 132 735
uint144	22 300 745 198 530 623 141 535 718 272 648 361 505 980 415
uint152	5 708 990 770 823 839 524 233 143 877 797 980 545 530 986 495
uint160	1 461 501 637 330 902 918 203 684 832 716 283 019 655 932 542 975
uint168	374 144 419 156 711 147 060 143 317 175 368 453 031 918 731 001 855
uint176	95 780 971 304 118 053 647 396 689 196 894 323 976 171 195 136 475 135
uint184	24 519 928 653 854 221 733 733 552 434 404 946 937 899 825 954 937 634 815
uint192	6 277 101 735 386 680 763 835 789 423 207 666 416 102 355 444 464 034 512 895
uint200	1 606 938 044 258 990 275 541 962 092 341 162 602 522 202 993 782 792 835 301 375
uint208	411 376 139 330 301 510 538 742 295 639 337 626 245 683 966 408 394 965 837 152 255
uint216	105 312 291 668 557 186 697 918 027 683 670 432 318 895 095 400 549 111 254 310 977 535
uint224	26 959 946 667 150 639 794 667 015 087 019 630 673 637 144 422 540 572 481 103 610 249 215
uint232	6 901 746 346 790 563 787 434 755 862 277 025 452 451 108 972 170 386 555 162 524 223 799 295
uint240	1 766 847 064 778 384 329 583 297 500 742 918 515 827 483 896 875 618 958 121 606 201 292 619 775
uint248	452 312 848 583 266 388 373 324 160 190 187 140 051 835 877 600 158 453 279 131 187 530 910 662 655
uint256	115 792 089 237 316 195 423 570 985 008 687 907 853 269 984 665 640 564 039 457 584 007 913 129 639 935